<template>
  <div class="spec-preview">
    <img :src="skuImg.imgUrl " />
    <div class="event" @mousemove="hander" ></div>
    <div class="big" >
      <img :src="skuImg.imgUrl " ref="big" />
    </div>
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
export default {
  name: "Zoom",
  props: ["skuImageList"],
  data() {
    return {
      currentIndex: 0,
    };
  },
  computed: {
    skuImg() {
      return this.skuImageList[this.currentIndex] || [];
    },
  },
  mounted() {
    //获取兄弟组件传递索引值
    this.$bus.$on("getIndex", (index) => {
      //修改当前响应式数据
      this.currentIndex = index;
    });
  },
  methods:{
    hander(event){
      let mask =this.$refs.mask
      let big=this.$refs.big
      let left=event.offsetX - mask.offsetWidth/2;
      let top =event.offsetY -mask.offsetHeight/2;
      //约束范围
      if(left<=0) left=0
      if(left>=mask.offsetWidth) left=mask.offsetWidth
      if(top<=0) top=0
      if(top>=mask.offsetHeight) top=mask.offsetHeight
      //修改元素left top属性值
      mask.style.left=left+'px'
      mask.style.top=top+'px'

      big.style.left=-2* left+'px'
      big.style.top=-2 *top+'px'
    }
  }
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>